The control of undesired vegetation is extremely important in achieving high crop efficiency. Achievement of selective control of the growth of weeds especially in such useful crops as rice, soybean, sugar beet, corn (maize), potato, wheat, barley, tomato and plantation crops, among others, is very desirable. Unchecked weed growth in such useful crops can cause significant reduction in productivity and thereby result in increased costs to the consumer. The control of undesired vegetation in noncrop areas is also important. Many products are commercially available for these purposes, but the need continues for new compounds which are more effective, less costly, less toxic, environmentally safer or have different modes of action.
World Patent Application Publication WO 92/05159-A discloses pyrimidines useful as plant protectants, especially fungicides. European Patent Application Publication EP-136976-A2 discloses pyrimidines as plant growth regulators. U.S. Pat. No. 5,324,710 discloses sulfonated heterocyclic carboxamide derivatives of pyrimidines as herbicides and growth regulators.